Malignancies with vascular pathologies are common, including cardiovascular diseases and most forms of cancers. Oxygenation in human tissues ranges from two to nine percent. Hypoxia is characterized by oxygen levels of less than two percent. Differing oxygenation has well established effects on physiology, including cancer progression and tissue ischemia in stroke. Due to irregular vascular function in many diseases, hypoxia occurs. The degree to which hypoxia varies as a function of distance from vasculature is highly variable due to differences in vascular malformation or injury, as well as inherent differences in diffusion of dissolved oxygen in different tissues. Direct measurement of tissue oxygenation in fixed surgically removed structures, however, is not possible.